/**
 * $RCSfile: PEPProvider.java,v $
 * $Revision: 1.2 $
 * $Date: 2007/11/06 02:05:09 $
 *
 * Copyright 2003-2007 Jive Software.
 *
 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jivesoftware.smackx.provider;

import java.util.HashMap;
import java.util.Map;

import org.jivesoftware.smack.packet.PacketExtension;
import org.jivesoftware.smack.provider.PacketExtensionProvider;
import org.xmlpull.v1.XmlPullParser;

/**
 * 
 * The PEPProvider parses incoming PEPEvent packets. (XEP-163 has a weird
 * asymmetric deal: outbound PEP are <iq> + <pubsub> and inbound are <message> +
 * <event>. The provider only deals with inbound, and so it only deals with
 * <message>.
 * 
 * Anyhoo...
 * 
 * The way this works is that PEPxxx classes are generic <pubsub> and <message>
 * providers, and anyone who wants to publish/receive PEPs, such as <tune>,
 * <geoloc>, etc., simply need to extend PEPItem and register (here) a
 * PacketExtensionProvider that knows how to parse that PEPItem extension.
 * 
 * @author Jeff Williams
 */
public class PEPProvider implements PacketExtensionProvider {

	Map<String, PacketExtensionProvider> nodeParsers = new HashMap<String, PacketExtensionProvider>();
	PacketExtension pepItem;

	/**
	 * Creates a new PEPProvider. ProviderManager requires that every
	 * PacketExtensionProvider has a public, no-argument constructor
	 */
	public PEPProvider() {
	}

	public void registerPEPParserExtension(String node,
			PacketExtensionProvider pepItemParser) {
		nodeParsers.put(node, pepItemParser);
	}

	/**
	 * Parses a PEPEvent packet and extracts a PEPItem from it. (There is only
	 * one per <event>.)
	 * 
	 * @param parser
	 *            the XML parser, positioned at the starting element of the
	 *            extension.
	 * @return a PacketExtension.
	 * @throws Exception
	 *             if a parsing error occurs.
	 */
	public PacketExtension parseExtension(XmlPullParser parser)
			throws Exception {

		boolean done = false;
		while (!done) {
			int eventType = parser.next();
			if (eventType == XmlPullParser.START_TAG) {
				if (parser.getName().equals("event")) {
				} else if (parser.getName().equals("items")) {
					// Figure out the node for this event.
					String node = parser.getAttributeValue("", "node");
					// Get the parser for this kind of node, and if found then
					// parse the node.
					PacketExtensionProvider nodeParser = nodeParsers.get(node);
					if (nodeParser != null) {
						pepItem = nodeParser.parseExtension(parser);
					}
				}
			} else if (eventType == XmlPullParser.END_TAG) {
				if (parser.getName().equals("event")) {
					done = true;
				}
			}
		}

		return pepItem;
	}
}
